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Bimetallic lined pipe (BLP) has been increasingly used in offshore and subsea oil and gas structures, but how to identify the invisible inner defects such as liner wall thinning and interface debonding is a challenge for future development. A nondestructive testing (NDT) method based on pulsed eddy current testing (PECT) has been proposed to face these difficulties. The inspection of the BLP specimen (AISI1020 base tube and SS304 liner) is implemented from outside of the pipe by using a transmitter–receiver-type PECT probe consisting of two induction coils. By simplifying the BLP specimen to stratified conductive plates, the electromagnetic field interaction between the PECT probe and specimen is analytically modeled, and the probe inspection signals due to liner wall thinning and interface debonding are calculated. In order to highlight the weak response (in microvolts) from the liner, the inspection signals are subtracted by the signal, which is calculated in the case of only having a base tube, yielding differential PECT signals. The peak voltage of the differential signal is selected to characterize the liner wall thinning and interface debonding due to its distinguishable and linear variation. Experiment verification is also carried out on a double-walled specimen simulated by a combination of a Q235 casing pipe and SS304 tubes of different sizes. The experimental results basically agree with the analytical predictions. The peak value of the PECT signal has an ascending and descending variation with the increase in the remaining liner wall thickness and debonding gap, respectively, while the negative peak value shows opposite changes. The peak value exhibits a larger sensitivity than the negative peak value. The proposed method shows potential promise in practical applications for the evaluation of the inner defects in BLP lines. [ABSTRACT FROM AUTHOR]

The over-extraction of groundwater has resulted in seawater intrusion and the southward migration of the saltwater interface, gradually deteriorating the groundwater quality in the Weibei Plain. In this research, groundwater samples were gathered from 46 monitoring wells for shallow groundwater during the years 2006, 2011, 2016, and 2021. The hydrochemical features of regional groundwater and the factors influencing the issue were subjected to statistical analysis. Additionally, the assessment of spatiotemporal variations in groundwater quality was conducted using the customized entropy-weighted water quality index (EWQI) method. The relationship between groundwater over-extraction and the southward intrusion of the saltwater interface was compared and analyzed. The results of this paper revealed that the Weibei Plain has been in a state of long-term over-extraction of groundwater from 2000 to 2021, with an average annual over-extraction of 118.49 million m3. The groundwater depression cone areas in the northern part of the study area increased from 3,247.37 to 4,581.34 km2 from 2006 to 2021, with the center of the cone experiencing a drop in groundwater level from -22 to -85 m. The saltwater interface shifted southward by 711.71 km2 from 2006 to 2021. In groundwater, the high concentrations of TH, TDS, and Cl- were primarily related to the seawater intrusion, while higher concentrations of NO3- were mainly determined by frequent agricultural production, industrial wastewater, and domestic sewage discharges. The groundwater hydrochemical types in the study area transitioned from predominantly HCO3 Ca-Mg type in 2006 to HCO3-Na type and SO4 Cl-Ca Mg type in 2021 due to seawater intrusion. The results of PCA and HCA show the effects of seawater intrusion, human activities, and rock weathering on groundwater hydrochemistry. The evaluation results based on the EWQI revealed that the average value of the samples in 2021 was 101.36, which belonged to Class IV water quality standards, representing the poorest water quality among the 4 years. The southward migration of the saltwater interface led to the deterioration of groundwater quality in the groundwater depression cone areas, which gradually worsened from 2006 to 2021. The maximum increase in EWQI value was 174.68 during the period, shifting from Class III water quality to Class V water quality. Groundwater quality remained relatively better in the western and southern regions which were less affected or unaffected by seawater intrusion. The results of the study can provide a certain reference value for the sustainable management of groundwater resources and the management of groundwater pollution and seawater intrusion in the Weifang City area in the future. [ABSTRACT FROM AUTHOR]

Desalination and power generation through solar energy harvesting is a crucial technology that can effectively address freshwater shortages and energy crises. However, owing to the complexity of the actual water environment, the thermal output capability of the photothermal material and the functional integration of the evaporation system need urgent improvement, to obtain high‐quality fresh water and sufficient electricity. Herein, a 2D/2D cesium tungsten bronze/copper sulfide (2D/2D Cs0.32WO3/CuS) nano‐heterojunction is developed and it is loaded into a cellulose‐based hybrid hydrogel to construct a multifunctional evaporator. Benefiting from the more nonradiative recombination centers from deep‐level defects, as well as shorter carrier migration distances and higher redox potentials in the Cs0.32WO3/CuS nano‐heterojunction, this evaporator has a significant improvement in thermal output capacity, enabling both super‐efficient seawater evaporation (4.22 kg m−2 h−1) and photodegradation of organic pollutants (removal rate ≈ 99%). Moreover, the evaporator exhibits long‐term stability and sustainable self‐cleaning property against salt accumulation. Remarkably, the thermoelectric module based on the Cs0.32WO3/CuS nano‐heterojunction shows promising electricity generation performance (4.85 W m−2), which can power small appliances durably and stably, exceeding previously reported similar devices. This 2D/2D heterojunction‐based solar evaporation system will provide a more reliable solution for efficient and sustainable freshwater‐electricity co‐generation in resource‐limited areas. [ABSTRACT FROM AUTHOR]

In the context of climate change, the problem of water scarcity is becoming increasingly serious, and improving the efficiency of water resources use is an important measure to alleviate this problem. The evaluation of water resources utilization efficiency has become the basis of water resource management. Data envelopment analysis (DEA) and analytic hierarchy process (AHP) are widely used in the evaluation of water resources utilization efficiency. However, one of these methods is mostly used for evaluation, which cannot reflect the influence of both objective and subjective factors. Therefore, in this study, we propose a water resources utilization efficiency index (WEI) to evaluate the water resources utilization efficiency of each region in the Tumen River Basin (TRB), combining both DEA and AHP methods. Firstly, the DEA-CCR model was used to quantify domestic, agricultural and industrial water use efficiency in the TRB. The DEA-BCC model was used to analyze the main influences on water use efficiency in each sector. Secondly, the WEI was constructed by assigning weights using the AHP model based on the importance of each water use sector. The results show that the WEI values for most areas within the TRB trended upwards between 2014 and 2019. In particular, domestic water use efficiency ranged from 0.294 to 0.775, while agricultural and industrial water use efficiency ranged from 0.039 to 0.054 and 0.031 to 0.375, respectively. Technical efficiency is the main factor influencing water use efficiency in TRB. This study could provide a basis for water resource management and mitigation of water scarcity in the context of climate change. [ABSTRACT FROM AUTHOR]

Low-cost and highly electroactive nickel-based materials are important electrodes for the development of supercapacitors. The precise modulation of the morphology and microstructure has been a crucial measure to further enhance the electrochemical performance. Herein, a three-dimensional porous nanocage NixS6/Ni(OH)2 hybrid formed by NixS6 nanoparticles anchored on Ni(OH)2 nanoflakes was creatively synthesized via a simple and scalable approach, which was based on two-time ion exchange reactions of the Mg(OH)2 precursor. Significantly, in asymmetric supercapacitors, the NixS6/Ni(OH)2 hybrid exhibits a high specific capacitance of 2726 F g−1 at a current density of 1 A g−1 and an excellent energy density of 31.31 Wh kg−1 at a power density of 62.56 W kg−1, which are superior to those of the currently reported nickel sulfide electrode materials. Compared with the nanoflower-like Mg(OH)2 and Ni(OH)2 precursors, the NixS6/Ni(OH)2 hybrid possesses hollow, abundant porous morphology and better electrical conductivity, which could provide a large contact surface area, shorter ion diffusion path and excellent charge transport, resulting in a dramatic improvement in electrochemical performance, making the NixS6/Ni(OH)2 hybrid a superb cathode material for supercapacitors. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable batteries have attracted attention owning to their advantages of safety, low cost, and sustainability, while the limited electrochemical stability window (1.23 V) of water leads to their failure in competition with organic‐based lithium‐ion batteries. Herein, we report an alkali–acid Zn–PbO2 hybrid aqueous battery obtained by coupling an alkaline Zn anode with an acidic PbO2 cathode. It shows the capability to deliver an impressively high open‐circuit voltage (Voc) of 3.09 V and an operate voltage of 2.95 V at 5 mA cm−2, thanks to the contribution of expanding the voltage window and the electrochemical neutralization energy from the alkali–acid asymmetric‐electrolyte hybrid cell. The hybrid battery can potentially deliver a large area capacity over 2 mAh cm−2 or a high energy density of 252.39 Wh kg−1 and shows almost no fading in area capacity over 250 charge–discharge cycles. [ABSTRACT FROM AUTHOR]

The europium/terbium ion-doped gadolinium orthophosphate nanorods and microcrystals phosphors were synthesized by the hydrothermal reaction and solid-phase reaction, respectively. The structures, morphologies, and luminescent behaviors were compared. The microcrystals can obtain higher quantum efficiency compared with nanorods because of the different structures (monoclinic and hexagonal). In the ultraviolet-visible region, the gadolinium ions absorbed energy then transferred to europium and terbium ions. The energy transfer from terbium to europium existed both in microcrystals and in nanorods, and it was confirmed that the energy transfer efficiency from terbium to europium in nanorods is higher than that in microcrystals. [ABSTRACT FROM AUTHOR]

Olivaceous two-dimensional (2D) multi-layer graphene-like Co3O4 thin sheets (CQU-Chen-Co-O-1) with vertically aligned nanosheets as basic building units were first prepared on a large scale by direct hydrothermal decomposition of a mixed aqueous solution of cobalt(ii) nitrate and acetic acid without the assistance of any template or surfactant. The resulting products exhibited excellent pseudocapacitive performance with a high specific capacitance of 1752 and 1862 F g−1 at the current density of 5 mV s−1 and 1 A g−1, respectively, as well as good rate capability (63.64% capacitance surplus) and high cycling performance (99.5% surplus after 2000 cycles). [ABSTRACT FROM AUTHOR]

Abstract: Sn1−x RE x O2−x/2 (RE=Y, La, Gd and Nd) nanorods have been prepared by annealing the as-obtained products from microwave-induced KCl-assisted solution combustion reaction. The phase evolution in the synthesis process was investigated by an X-ray diffractometer. Accordingly, the possible growth mechanism of Sn1−x RE x O2−x/2 nanorods was discussed based on oriented attachment by polar forces. The results showed that the Sn0.8Y0.2O1.9 nanorods were rutile-structured single crystals with 8–12nm diameter and 100–200nm length. Proper addition of KCl into the redox mixture solution is critical to the formation of Sn1−x RE x O2−x/2 nanorods. The approach is convenient, inexpensive and efficient for the high yield preparation of Sn1−x RE x O2−x/2 nanorods. [Copyright &y& Elsevier]

Abstract: Y2O3:Eu3+ nanophosphors were fabricated by direct thermal decomposition of monohydrate yttrium europium propionates, which can be facilely obtained via cocrystallization. The composition and structure of the cocrystallized product were confirmed by X-ray diffractionmetry (XRD), simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) as well as inductively coupled plasma mass (ICP-MS) spectrometry. The effects of decomposition temperature on the resultant microstructures such as crystallinity, particle size and particle dispersibility were investigated by XRD and transmission electron microscopy (TEM). The dependence of their luminescent properties on decomposition temperature was also studied by fluorescence spectrophotometry. The results showed that the microstructures and luminescent intensities of Y2O3:Eu3+ nanophosphors could be tuned by varying calcination temperatures of cocrystallized yttrium europium propionates from 600 to 1000°C. [Copyright &y& Elsevier]